Up to 12% of Australians may experience some gambling harms. Reducing gambling could prevent these harms. This study looked at how a person’s gambling cravings and their confidence in resisting their cravings (i.e., self-efficacy) influence their gambling behaviour, and vice versa. Adults who gambled regularly completed short surveys twice per day for four weeks. Participants who had gambling cravings were more likely to gamble at a later time. Participants with lower craving self-efficacy spent more money gambling. If cravings were infrequent, then high gambling self-efficacy reduced gambling episodes. However, if cravings were frequent, then self-efficacy did not reduce gambling. Participants who gambled to cope spent more money gambling if they had low gambling self-efficacy. Finally, participants who gambled for positive reinforcement and those with substance use issues were more vulnerable to gambling.